MESS is to computers and consoles as MAME is to arcade machines. i.e. It is an attempt to exactly emulate early computer and console systems. It is based primarily on the MAME source code so versions run in parallel to MAME. The reason MESS can use MAME as a basis is that most chips in computers and consoles are direct copies of arcade chips just connected a different way. In the guide you need to be aware of some terminology. If I use the word system it means the computer or console system being emulated. If I use the word BIOS it is meant to be for system roms or BIOS images used to get MESS working. Finally if I use the word software it means the rom/tape/disk etc… image to be loaded onto the system running in MESS. The following is a list of changes in this update:

0.121

New System Drivers Supported (in no particular order):
——————————————————
– Acorn System 1 [Dirk Best] (not working)
– Atari STBook [Curt Coder] (not working)
– BBC Bridge Companion [Phil Bennet, incog] (not working)
– HKT-0120 Sega Dreamcast Development Box [incog] (not working)
– Osborne-1 [Wilbert Pol, Cowering]
– Spectravideo SVI-318 (NTSC) [Tomas Karlsson]
– Spectravideo SVI-328 (NTSC) [Tomas Karlsson]
– Synertec Systems Corp. SYM-1 [Dirk Best] (not working)
– VG-8020 [incog]

System Driver Changes:
———————-
– [ADAM] Input ports cleanup, natural keyboard support. [Stefano Priore]

– [ATARIST] Implemented iKBD<->68000 communications, so the keyboard is working
now. [Curt Coder]

– [BEBOX] Fixed VGA regression introduced in 0.119. [Tomas Karlsson]

– [COCO] Updated to use MAME’s 6242 RTC implementation. [tim lindner]

– [COCO] Modified the CoCo’s keyboard handler to pass along the tri-state
buffer from port B to port A. [tim lindner]

– [GAMEGEAR] Fixed graphics issues in Ax Battler. (bug #1332) [Wilbert Pol]

– [GAMEGEAR/SMS] Allow the VDP status bits to be read before an
interrupt is triggered and handled. Fixes hang in first level of
Zool. (bug #1419) [Wilbert Pol]

– [GAMEGEAR/SMS] The internal video data buffer should hold the data written
to the data port. (bug #1378 and bug #1418) [Wilbert Pol]

– [MEPHISTO] Implemented artwork/code for real chess board usage. [Ralf
Schäfer, Cowering]

– [ORIC] Fixed floppy interface detection. [Dirk Best]

– [PET] Updated to use MAME’s CRTC6548 implementation. [Wilbert Pol]

– [PET] Fixed keyboard regression introduced in 0.116. (bug #1405) [Wilbert
Pol]

– [QL] The system is now usable, except that microdrives don’t work yet. [Curt
Coder]

– [SVI318] Fixed borders. Added selectable bioses for all models.
Added serial port support. Added support for NTSC models. [Tomas Karlsson]

– [SVI318] Fixed a bug in banking for SVI-328 with 64KB RAM. Added SVI806
80 column card support. [Wilbert Pol]

– [SVI328] Fixed numeric pad input ports. [Tomas Karlsson]

– [SYM1] Rewrote, still many issues and doesn’t fully work. [Dirk Best]

– [TI99] Fixed TI99 border regression. [Michael Zapf]

– [X68000] Raster effects, DMA and vblank improvements. [Barry Rodewald]

User Interface Changes:
———————–
(none)

Imgtool Changes:
—————-
(none)

Source Changes:
—————-
– The core is based on MAME 0.121. This incorporates all features of the
update to this core. [MAME team]

Download at our MESS page.